NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

New National Wind Potential Estimates for 

Modern and Near-Future Turbine Technologies

Joseph “Owen” Roberts

National Renewable Energy Laboratory

ASES SOLAR 2014

San Francisco, California

July 6–10, 2014

NREL/PR-5000-62318
2

Presentation Overview

• What has changed in the past 5–10 years in turbine 

technology and pricing?

• What areas could potentially be developed with new 

technologies?

• What is the new national potential for land-based 

wind technology in the near future?
3

Key Developing Turbine Technologies

• Blade length:

• Longer blades increase capacity factor

• Industry trending towards lower specific power

• Tower height:

• U.S. market currently constrained

• GE to commercially offer 140-m towers in 2015 in Europe, 

future towers may reach up to 160 m. 
4

Lower Specific Power Trend

4

• Longer blades increase capacity factor

• Industry trending towards lower specific power.

Wiser, R.; Bollinger, M. (2012). 2012 Wind Technologies Market Report. Washington, DC: U.S. Department of Energy. Accessed June 24, 2014: 

https://www1.eere.energy.gov/wind/pdfs/2012_wind_technologies_market_report.pdf; p. 46
5

Capacity Factor Trends

5

• Average capacity factor (CF) nearly constant in spite of lower 

average wind resource

• Lower specific power turbines increase developable area.

Wiser, R.; Bollinger, M. (2012). 2012 Wind Technologies Market Report. Washington, DC: U.S. Department of Energy. Accessed June 24, 2014: 

https://www1.eere.energy.gov/wind/pdfs/2012_wind_technologies_market_report.pdf; p. 45 
6

Assumptions for Wind Potential Study

• Wind data from AWS Truepower 200-m resolution binned data at 20-

km resolution, long-term adjusted hourly wind speed data

• GE 1.62-100, GE 1.62-82.5, GE 1.5-77, Nordex N117-2.4 turbines

• Wind data adjusted for altitude and appropriate International 

Electrotechnical Commission (IEC) class turbine selected for average 

annual wind speed

• These maps and statistics exclude all urban areas, bodies of water, 

national parks, and half of the area of U.S. Forest Service lands

• Shading is raw area available land (darker blue is the more available 

area).
7

Past Estimates – Gross CF>30% IEC Class 2 80-m Hub Height

Source: Donna Heimiller, NREL
8

New Estimates – Gross CF>30% GE 1.62-100 80-m Hub Height

• Increase in raw area available ~50.6% over previous estimate.

Source: Donna Heimiller, NREL
9

Areas of New Potential Development

• Map below shows the difference in the previous two maps. 

Source: Donna Heimiller, NREL
10

New Estimates (Gross CF>40% N117-2.4 140-m Hub Height)

Source: Donna Heimiller, NREL

• Potentially developable area in southern states utilizing existing turbine technology. 
11

Current Technology Potential

• Assumes N117-2.4 140-m hub height, 40% gross capacity 

factor (GCF), 2.6 MW/km2

• Total area developable assuming typical exclusions 

• Total potential 134 GW for southern states (shown below).

0

10000

20000

30000

40000

50000

60000

AL FL GA LA MS NC SC TN VA

Potential MW by State 140m HH, N117-2.4 40% GCF, 2.6MW/km^2

Potential MW

Caveat- Uncertainty in this wind data is high as little validation data is available at these hub 

heights.
12

Barriers to Wind Development in New Markets

• Federal Aviation Administration height restriction creates 

uncertainty for permitting taller towers

• Local communities not accustomed to wind development

• Transportation infrastructure for turbine components might 

need adjustments and requires detailed scheduling

• Conventional tower technology (base diameter)

• Crane availability for tall towers and heavy nacelles may be 

limited, potential for new technologies

• Wildlife habitat, flight, and migration areas require 

appropriate siting.
13

Questions?

Buffalo Mountain Wind Farm

Oak Ridge, Tennessee

Joseph “Owen” Roberts

NREL National Wind Technology Center

joseph.roberts@nrel.gov

303-384-7151

Photo by Joseph Owen Roberts, NREL